Fixed changelog link.

Author: jkbrzt

README.rst

@@ -1405,6 +1405,6 @@ Changelog
 .. _0.6.0: https://github.com/jkbr/httpie/compare/0.5.1...0.6.0
 .. _0.7.1: https://github.com/jkbr/httpie/compare/0.6.0...0.7.1
 .. _0.8.0: https://github.com/jkbr/httpie/compare/0.7.1...0.8.0
-.. _0.9.0-dev:: https://github.com/jkbr/httpie/compare/0.8.0...master
+.. _0.9.0-dev: https://github.com/jkbr/httpie/compare/0.8.0...master
 .. _AUTHORS.rst: https://github.com/jkbr/httpie/blob/master/AUTHORS.rst
 .. _LICENSE: https://github.com/jkbr/httpie/blob/master/LICENSE